I got an iPad a week ago. I wanted something to play games on away from my desktop computer. I was lured by a game called The Room, which I read a review on. I'm a true adventer gamer, I love Myst-like puzzles discovery games. While The Room is exactly that (a room), you get to explore puzzles boxes in 3D. It's like Safecracker, but with the ability to turn and manipulate objects. I haven't felt this sort of wonder since I first played Riven a long time ago.
Here's a list of games I'm looking into for my iPad.
Forever Lost
The Witness
Kairo (I was going to get this for my PC anyhow)
Infernus Verse
Flee
The Haunt 1 and 2
Tesla's Electric Mist
There are some good puzzle games too. I like the ability to use the mechanics of the iPad in the solve - tilting or shaking. It adds another twist to the puzzles. I'm playing 100 Floors right now and it really gets you thinking outside the box.
Between my Windows computer and my Ipad, I have more selection for the games I like to play than I've had in a long while.